Tags_demo problem

GNU Radio
#1

Hi list,

Today I was trying to run one of the examples that come with gr-uhd
“tags_demo” to schedule my burst transmission . I have USRP N210.
RFX2400.
linux; GNU C++ version 4.6.3; Boost_104601; UHD_003.005.000-26-gb65a3924

I want burst duration and idle duration of 0.012 and 1 seconds
respectively. So, I tried following command

./tags_demo --burst 0.012 --idle 1

I observed that LED “A” on USRP flashes for very short period of time,
and
that I think is right because of short burst duration 12ms indicating
transmission, after 1 sec idle duration. Question I want to ask is even
if
I kill the flow graph using Ctrl+C, LED “A” keeps on flashing with same
behavior for some time and then finally stops. Why is that so?

Also, LED “E” which was static while flow graph was running, blinks
intermittently when flow graph has been stopped. But I think thats
normal.

Regards,

Sam

#2

On 05/20/2013 11:41 PM, Sam mite wrote:

I observed that LED “A” on USRP flashes for very short period of time, and
that I think is right because of short burst duration 12ms indicating
transmission, after 1 sec idle duration. Question I want to ask is even if
I kill the flow graph using Ctrl+C, LED “A” keeps on flashing with same
behavior for some time and then finally stops. Why is that so?

Most likely, many transmit bursts are queued up on the device. The
example code that produces timed bursts doesnt wait for particular user
control or feedback from rx packets, its just sending out samples w/
burst tags – which there is some finite amount of buffering upstream to
hold.

Also, LED “E” which was static while flow graph was running, blinks
intermittently when flow graph has been stopped. But I think thats normal.

Thats ok, its just the ref lock light on a partially powered down
synthesizer.

Cheers,
-josh